Atrial appendage closure device and related methods

ABSTRACT

An atrial appendage closure device is provided that includes an insertion rod having a first end and a second end. An occluding member having an outer surface and an inner surface is connected to the first end of the insertion rod. The occluding member is moveable between a retracted position and a deployed position such that, in the deployed position, the occluding member is configured to provide a seal between a left atrial appendage and a left atrium of a heart. An anchoring member is further connected to the insertion rod and is configured to slide along the insertion rod to secure the device to a wall of a left atrial appendage. Methods for occluding a left atrial appendage that make use of the closure devices are also provided.

RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application Ser.No. 61/676,157, filed Jul. 26, 2012, and 61/791,147, filed Mar. 15,2013, the entire disclosures of which are incorporated herein by thisreference.

TECHNICAL FIELD

The presently-disclosed subject matter relates to an atrial appendageclosure device. In particular, the presently-disclosed subject matterrelates to an atrial appendage closure device having an insertion rodand an occluding member, which, in a deployed position, is configured toprovide a seal between a left atrial appendage and a left atrium of aheart.

BACKGROUND

In the United States, there are approximately three million patientswith atrial fibrillation (AF), and this number is expected to increaseto five million by 2040. AF is an irregular sinus rhythm and atrialdysrhythmia, which results in a rapid, irregular, and unsynchronizedcontraction of the atrium. In AF, blood is not washed from the leftatrial appendage and it stagnates and tends to clot inside the heart.However, these clots are prone to leaving the heart and embolizing todifferent organs in the body. For example, it has been observed that theclots frequently leave the heart and enter the cerebral vessels,resulting in an embolic stroke. Indeed, patients with AF are at asignificantly increased risk of stroke, and it is estimated thatpatients with AF have, on average, 5 to 6 times greater probability ofhaving a stroke (5-15% annualized risk of stroke) and 18 times greaterprobability of having an embolic event. This risk of stroke with AF onlyincreases with age, with up to 30% of all strokes in elderly patientsoccurring due to AF, and with, overall, at least 100,000 strokes peryear being attributed to AF in the United States alone.

Medical and ablation therapies have been used to attempt to eliminateAF, but most patients continue to remain in AF after therapy. In thisregard, current treatment of AF often includes anticoagulation therapywith warfarin, which has been reported to reduce the risk of stroke by62%, but requires close monitoring to prevent bleeding complicationsthat may otherwise result in mortality. In fact, even with closeattention to warfarin dosing, life-threatening bleeding complications,intracerebral bleeding, or death still occurs in 1-2.5% of thesepatients every year, with the highest risk of warfarin complicationsbeing in elderly patients, who are also at the highest risk of strokedue to AF. Due to this risk, it is estimated that 40% to 65% of elderlypatients with AF and at an increased risk of stroke are not receivinganticoagulant therapy with warfarin. However, it has further beenestimated that 35% of patients with AF who are not treated withanticoagulants will likely have a stroke during their lifetime.

Antiplatelet therapy with aspirin has been proposed as a possiblealternative to warfarin therapy, but to date has not proven to be veryeffective. Similarly, combination therapy with aspirin and clopidogrelhas also not proven to be as effective in preventing clot formation aswarfarin. New pharmaceutical agents aimed at factor Xa and thrombininhibition anticoagulant agents, such as Pradaxa® (Boehringer IngelheimPharma GmbH & Co. KG; dabigatran etexilate) have provided similarreductions in stroke rates and less monitoring when compared towarfarin. Nevertheless, many of these agents, including Pradaxa® arecontraindicated for patients over 75, have been shown to still result inbleeding complications, and still require compliance from elderlypatients who often forget to take their oral medications.

To overcome these limitations of pharmaceutical agent-based therapiesfor treating AF, catheter-based left atrial appendage occluder devices,such as AMPLATZER® (AGA Medical Corporation), PLAATO® (EV3Inc.), andWATCHMAN® (Atritech, Inc.), as well as other devices such as theTIGERPAW® system (LAAx, Inc.) and ATRICLIP® (AtriCure, Inc.) haverecently been developed. Initial reports regarding the use of thesedevice-based therapies to block the left atrial appendage have providedgood results, and have shown that the devices can reduce hemorrhagicstroke as compared to warfarin therapy. However, recent clinical trialswith these devices have also shown an associated increase in ischemicstroke, which is in addition to the fact that the implantation of thedevices requires a delivery catheter to puncture the atrial septum aswell as barbs for anchoring the devices, both of which can lead toseveral complications including puncturing of the left atrium. Moreover,these current left atrial appendage closure devices are not alwayscompletely effective in sealing off the left atrial appendage due topatient-to-patient variability in left atrial appendage sizes, thusleading to embolic clots. Further, it is also possible that any foreignmaterial in the left atrial appendage may also cause thrombus formation.Accordingly, an atrial appendage closure device that avoids the adverseevents common with current catheter-based left atrial appendage occluderdevices or common with current pharmaceutical therapies would be bothhighly-desirable and beneficial.

SUMMARY

The presently-disclosed subject matter meets some or all of theabove-identified needs, as will become evident to those of ordinaryskill in the art after a study of information provided in this document.

This summary describes several embodiments of the presently-disclosedsubject matter, and in many cases lists variations and permutations ofthese embodiments. This summary is merely exemplary of the numerous andvaried embodiments. Mention of one or more representative features of agiven embodiment is likewise exemplary. Such an embodiment can typicallyexist with or without the feature(s) mentioned; likewise, those featurescan be applied to other embodiments of the presently-disclosed subjectmatter, whether listed in this summary or not. To avoid excessiverepetition, this summary does not list or suggest all possiblecombinations of such features.

The presently-disclosed subject matter includes an atrial appendageclosure device. In particular, the presently-disclosed subject matterincludes an atrial appendage closure device having an insertion rod andan occluding member, which, in a deployed position, is configured toprovide a seal between a left atrial appendage and a left atrium of aheart.

In one exemplary embodiment of the presently-disclosed subject matter,an atrial appendage closure device is provided that comprises aninsertion rod having a first end and a second end. The atrial appendageclosure device further includes an occluding member that is connected tothe first end of the insertion rod. The occluding member includes anouter surface and an inner surface. Also included in the atrialappendage closure device is an anchoring member that is connected to orotherwise attached to the insertion rod for securing the device to awall of the left atrial appendage.

The insertion rods of the exemplary atrial appendage closure devices aregenerally constructed from a metal or plastic material to provide aninsertion rod having a sufficient amount of strength to allow it to beinserted into the wall of an atrial appendage of a heart and retain itsshape. In this regard, the insertion rod can be in the form of a solidinsertion rod (e.g., a wire) or can be in the form of a tube-likestructure where the insertion rod defines a hollow interior cavity andan opening at the second end of the insertion rod. In some embodiments,such a hollow insertion rod can further define a plurality offenestrations that are in fluid communication with the hollow interiorcavity and the opening at the second end of the insertion rod, suchthat, upon using the occluding member to seal off a left atrialappendage, the fenestrations can be used to remove blood or fluid fromthe left atrial appendage.

With regard to the occluding member, the occluding member is moveablebetween a retracted position and a deployed position. The occludingmember is typically comprised of a flexible material or membrane that issupported by a plurality of ribs radiating from the center of theoccluding member to thereby provide a flexible structure that is capableof being moved between the retracted position and the deployed position.In the retracted position, the occluding member is positioned adjacentto and extends along the length of the first end of the insertion rod.In the deployed position, however, the occluding member generallyassumes an umbrella-like shape, such that the occluding member is thenconfigured to provide a seal between a left atrial appendage and a leftatrium of a heart. In this regard, in some embodiments, in a deployedposition, the outer surface of the occluding member assumes a concaveshape and the inner surface of the occluding member assumes a convexshape. In other embodiments, in a deployed position, the outer surfaceof the occluding member assumes a convex shape and the inner surface ofthe occluding member assumes a flattened shape. In some embodiments, tofurther assist in sealing off the left atrial appendage from the leftatria of a heart, the occluding member further includes a hooked portionat each end of the outer surface of the occluding member.

To further facilitate the use of the atrial appendix closure devices ofthe presently-disclosed subject matter and promote the integration ofthe devices into the heart of a subject, the outer surface, the innersurface, or both the outer surface and the inner surface of theoccluding member are coated with an extracellular matrix In someembodiments, to facilitate the use of the devices and promote theirintegration, the outer surface, the inner surface, or both the outersurface and the inner surface of the occluding member are coated with agrowth factor.

With regard to the anchoring members included in the exemplary atrialappendage closure devices of the presently-disclosed subject matter,each anchoring member is generally connected to and configured to slidealong the insertion rod. In certain embodiments, the anchoring member isin the form of a bolt that can be slid along the insertion rod andagainst the wall of an atrial appendage before being locked in place tosecure the device to the wall of the left atrial appendage. In otherembodiments, and similar to the occluding member, the anchoring memberis movable between a retracted position and a deployed position, and hasan umbrella-like shape with the proximal surface of the anchoring memberbeing flat and the distal surface of the anchoring member having aconvex shape.

Further provided by the presently-disclosed subject matter are methodsof occluding a left atrial appendage. In one exemplary implementation ofa method of occluding a left atrial appendage, a closure device is firstprovided that includes: an insertion rod having a first end and a secondend; and an occluding member that has an outer surface and an innersurface and is connected to the first end of the insertion rod, with theoccluding member being moveable between a retracted position and adeployed position. Upon providing the closure device, the occludingmember and a portion of the insertion rod is then inserted into the leftatrial appendage and into a left atrium of a heart by piercing the wallof the left atrial appendage and inserting the occluding member and theportion of the insertion rod while the occluding member is in aretracted position. Once inserted, the occluding member is then deployedinside the left atrium, such that the occluding member is now configuredto provide a seal between the left atrial appendage and the left atriumof the heart. Subsequently, the inner surface of the occluding member ispulled toward the tip of the left atrial appendage, and the left atrialappendage is collapsed against and secured to the inner surface of theoccluding member. In certain implementations that make use of ananchoring member in the closure devices, securing the inner surface ofthe occluding member against the wall of the left atrial appendage isthen further accomplished by securing the anchoring member against thewall of the left atrial appendage opposite the inner surface of theoccluding member to thereby provide a seal between a left atrialappendage and the left atrium of the heart.

Further features and advantages of the presently-disclosed subjectmatter will become evident to those of ordinary skill in the art after astudy of the description, figures, and non-limiting examples in thisdocument.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a cross-section of a human heartshowing an atrial appendage closure device made in accordance with thepresently-disclosed subject matter and inserted into the left atrialappendage of the heart;

FIGS. 2A-2B are side views of an atrial appendage closure device made inaccordance with the presently-disclosed subject matter, and showing thedevice in a retracted position (FIG. 2A) and in a deployed position(FIG. 2B);

FIG. 3 is a schematic representation of an exemplary method of occludinga left atrial appendage in accordance with the presently-disclosedsubject matter, in which an atrial appendage closure device of thepresently-disclosed subject matter is deployed to provide a seal betweenthe left atrial appendage and the left atrium of a heart;

FIG. 4 is a schematic representation similar to FIG. 3, but furthershowing the wall of the left atrial appendage partially collapsedagainst the inner surface of the occluding member of the atrialappendage closure device;

FIG. 5 is a schematic representation similar to FIGS. 3-4, but furthershowing the wall of the left atrial appendage completely collapsedagainst the inner surface of the occluding member of the atrialappendage closure device;

FIG. 6 is a schematic representation similar to FIGS. 3-5, but furthershowing an epithelial cell layer coating the outer surface of theoccluding member of the atrial appendage closure device;

FIG. 7 is a schematic representation of another exemplary method ofoccluding a left atrial appendage in accordance with thepresently-disclosed subject matter, in which another atrial appendageclosure device of the presently-disclosed subject matter is used tocollapse a left atrial appendage;

FIG. 8 is a schematic representation similar to FIG. 7, but furthershowing the left atrial appendage fully collapsed;

FIG. 9 is a side view of the left atrial appendage closure device usedin accordance with the methods depicted in FIGS. 7 and 8;

FIG. 10 is a front view of the left atrial appendage closure deviceshown in FIGS. 7-9, but further illustrating an extracellular matrix andgrowth factors coating the outer surface of the occluding member of thedevice;

FIG. 11 is a side view of another atrial appendage closure device of thepresently-disclosed subject matter, and showing the further device in adeployed position; and

FIGS. 12A-12N are a series of schematic representations showing anotherexemplary method of occluding a left atrial appendage in accordance withthe presently-disclosed subject matter, in which the atrial appendageclosure device of FIG. 11 is used to provide a seal between the leftatrial appendage and the left atrium of a heart.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The presently-disclosed subject matter is an atrial appendage closuredevice and, more particularly, an atrial appendage closure device havingan insertion rod and an occluding member, which, in a deployed position,is configured to occlude and provide a seal between a left atrialappendage and a left atrium of a heart.

Referring first to FIG. 1 and FIGS. 2A-2B, an exemplary atrial appendageclosure device 10 made in accordance with the presently-disclosedsubject matter includes an insertion rod 20 having a first end 22 and asecond end 24. The atrial appendage closure device 10 further includesan occluding member 30 that is connected to the first end 22 of theinsertion rod 20. The occluding member 30 includes an outer surface 32and an inner surface 34. Also included in the atrial appendage closuredevice 10 is an anchoring member 40 in the form of a bolt that isconnected to or otherwise attached to the insertion rod 20 for securingthe device 10 to the left atrial appendage 100 of a heart 120.

With regard to the occluding member 30, and referring more specificallynow to FIGS. 2A-2B, the occluding member 30 is moveable between aretracted position and a deployed position. As shown in FIG. 2A, in theretracted position, the occluding member 30 is positioned adjacent toand is attached to the first end 22 of the insertion rod 20, such thatthe outer surface 32 and the inner surface 34 of the occluding member 30extend along a length of the insertion rod 20. However, as shown in FIG.2B, in the deployed position, the insertion rod 20 assumes anumbrella-like shape with the outer surface 32 of the occluding member 30assuming a concave shape and the inner surface 34 of the occludingmember 30 assuming a convex shape, such that the occluding member 30 isthen configured to provide a seal between the left atrial appendage andthe left atrium of the heart. Of course, it is also contemplated that,upon deployment, the outer surface and the inner surface of theoccluding member can be constructed such that the surfaces of theoccluding member assume various other shapes to accommodate the anatomyof a particular heart and/or to accommodate a desired application. Forexample, in certain embodiments, an occluding member can include anouter surface that is convex and an inner surface that is concave. Asanother example, in a further embodiment, an occluding member 230 ofanother exemplary atrial appendage closure device 210 includes anoccluding member 230 that, upon deployment, has a convex outer surface232 and a substantially flat inner surface 234, as shown in FIGS. 7-9.

Regardless of the ultimate configuration of the occluding member upondeployment, and as perhaps best shown in FIG. 2B, the occluding member30 is typically comprised of a flexible material or membrane 38 that issupported by a plurality of ribs 39 and/or a reinforcing mesh to therebyprovide a flexible structure that is capable of being moved between aretracted and deployed position, but yet is still sufficiently rigidsuch that the occluding member 30 can provide an effective seal betweenthe left atrial appendage and left atrium of a heart and will notcollapse into the left atrial appendage upon being exposed to the bloodflow in the heart and the pressure generated by the left atrium. In someembodiments, the occluding member is comprised of a plastic, a metal, ashape memory alloy, such as Nitinol, or combinations thereof.

With regard to the insertion rod 20 of the exemplary atrial appendageclosure device 10, the insertion rod 20 is in the form of a solid rodand is generally constructed from a metal or plastic material to providean insertion rod having a sufficient strength to allow it to be insertedinto the wall of an atrial appendage of a heart and retain its shape.However, as a refinement to the atrial appendage closure devices of thepresently-disclosed subject matter and, in particular, to the insertionrods of the devices, in a further embodiment, an atrial appendageclosure device 210 is provided where the insertion rod 220 defines ahollow interior cavity 272 and an opening 274 at the second end 224 ofthe insertion rod, as shown in FIGS. 7-9. The hollow insertion rod 220further defines a plurality of fenestrations 270 that are in fluidcommunication with the hollow interior cavity 272 and the opening 274 atthe second end 224 of the insertion rod 220. In this regard, uponinsertion of the device 210, the deployment of the occluding member 230,and the securing of the inner surface 234 and outer surface 232 of theoccluding member 230 to provide a seal between the left atrial appendage100 and the left atria of a heart, a vacuum can be applied to theopening 274 and the fenestrations 270 can be used to remove blood fromthe left atrial appendage 100 while also facilitating the collapsing ofthe left atrial appendage 100 against the inner surface 234 of theoccluding member 230, as shown best in FIGS. 7-8. Similarly, by makinguse of the opening 274 and the fenestrations 270, radio-opaque dyes canbe injected through the insertion rod 220 to check the positioning ofthe device 210 and the integrity of the seal provided by the device 210.

Referring now to FIG. 10, to further facilitate the use of the atrialappendage closure device 210, the outer surface 232 of the occludingmember 230 is coated with an extracellular matrix 238 and growth factors237 using methods known to those of ordinary skill in the art. As usedherein, the term “growth factor” is used to refer to a substance capableof stimulating cellular growth, proliferation, and cellulardifferentiation. Such growth factors include, but are not limited to,vascular endothelial growth factor (VEGF), basic fibroblast growthfactor (bFGF), insulin-like growth factor (IGF), placental growth factor(PIGF), Angl, platelet derived growth factor-BB (PDGF-BB), andtransforming growth factor β (TGF-β), and combinations thereof. Ofcourse, as would be recognized by those of ordinary skill in the art,various other materials and biological molecules can be attached to orused to coat a atrial appendage closure device of thepresently-disclosed subject matter, and can be selected for a particularapplication as desired.

The term “extracellular matrix” is used herein to refer to theextracellular network of polysaccharides and proteins that typicallyserve as structural elements to the cells and tissues of a body and thatprovide a supporting and attachment surface for epithelial cells. Inthis regard, the term “extracellular matrix” is inclusive of thecollection of polysaccharides and proteins that make up theextracellular matrix, but is further used to refer to the individualpolysaccharides and proteins that make up the extracellular matrix, aswell as the cells, such as fibroblasts and chondrocytes, that contributeto the development of the extracellular matrix. Exemplarypolysaccharides and proteins of the extracellular matrix include, butare not limited to: proteoglycans, such as heparin sulfate, chondroitinsulfate, and keratin sulfate; non-proteoglycan polysaccharides, such ashyaluronic acid; collagen; elastin; fibronectin; and laminin.

Referring now to FIG. 6, by including an extracellular matrix (notshown) on the occluding member 30, the device 10 can be configured so asto promote epithelialization or, in other words, to promote thedeposition of epithelial cells and the growth of an epithelial celllayer 36 over the surface of the device 10. In this regard, by promotingepithelialization over the device 10, the device 10 is kept from beingdirectly exposed to the circulating blood within the heart of a subjectand scar tissue formation, immune reactions, or any other adverse eventscommonly associated with the implantation of a foreign body into aliving subject are thereby minimized or prevented. In some embodiments,the outer surface of an exemplary occluding member is coated with anextracellular matrix, growth factors, or both to promoteepithelialization or the formation of an epithelial cell layer over theentire surface of the occluding member that is placed into directcontact with the left atrium of a heart. Of course, it is alsocontemplated that the inner surface of an exemplary occluding member, orany other portion of an exemplary atrial appendage closure device, canalso be coated with an extracellular matrix or with growth factorswithout departing from the spirit and scope of the subject matterdescribed herein. For example, with reference to FIGS. 3-6, it iscontemplated that the insertion rod 20 of the device 10 can be coatedwith an extracellular matrix such that, upon insertion of the device 10,there is not an area of the device 10 where cells are not able to adhereor where a hole may be created between the device 10 and the surroundingtissue, which may then lead to blood stasis and blood clot formation.

Referring still to FIGS. 3-6, further provided by thepresently-disclosed subject matter are methods of occluding a leftatrial appendage that make use of the exemplary atrial appendage closuredevice 10 of the presently-disclosed subject matter. In one exemplaryimplementation of a method of occluding a left atrial appendage inaccordance with the presently-disclosed subject matter, the atrialappendage closure device 10 is first provided and, while in a retractedposition, the occluding member 30 and a portion of the insertion rod 20are inserted into the left atrial appendage 100 and the left atrium 110by piercing the wall 102 of the left atrial appendage 100 and thenpushing the occluding member 30 and the portion of the insertion rod 20through the left atrial appendage 100 and into the left atrium 110. Bymaking use of an occluding member 30 that is moveable between aretracted position and a deployed position, the occluding member 30 ofthe device 10 can advantageously be placed into its retracted position(shown in FIG. 2A) and subsequently inserted into the left atrialappendage of 100 of a heart by performing only a minimally invasivethoracotomy with a small (e.g., approximately 1 inch) incision, similarto those used in laparoscopic procedures. Of course, the device 10 canalso be inserted as part of other, more invasive cardiac or vascularsurgical procedures. However, without wishing to be bound by anyparticular theory, it is believed that by inserting the device 10 via aminimally invasive thoracotomy, implantation complications areminimized, as small thoracotomies have been shown to have lesscomplications than other procedures that involve puncturing of theatrial septum using catheter or guidewire techniques commonly utilizedin percutaneous approaches.

Regardless of the particular surgical approach used to insert theoccluding member 30 and the portion of the insertion rod 20, as shown inFIG. 3, once the occluding member 30 is inserted inside the left atrium110, the occluding member 30 is deployed such that the outer surface 32of the occluding member 30 assumes a concave shape, the inner surface 34of the occluding member 30 assumes a convex shape, and the entirety ofthe occluding member 30 covers an area significantly beyond the openingof the left atrial appendage 100. Then, as shown in FIG. 4, while in adeployed position, the occluding member 30 and the remainder of theinserted portion of device 10 are pulled towards the tip 104 of the leftatrial appendage 100. As shown in FIG. 5, the left atrial appendage 100is then collapsed, such as by using a vacuum or other mechanical force,and the anchoring member 40 is slid along the length of the insertionrod 20 and is attached to the tip 104 of the left atrial appendage 100to thereby completely secure the inner surface 34 of the occludingmember 30 against the wall 102 of the left atrial appendage 100 and tothereby provide a complete seal between the left atrial appendage 100and the left atrium 110 of the heart. Lastly, a portion of the insertionrod 20, including the second end 24 of the insertion rod 20 is cut awayor broken at a user-defined length adjacent to the anchoring member 40(or can be further filled with a filler to seal off the hollow interiorif a hollow insertion rod is used, such as the hollow insertion rodshown in FIGS. 7-9).

Referring now to FIGS. 11 and 12A-12N, as a refinement to the atrialappendage closure devices and methods of the presently-disclosed subjectmatter, an atrial appendage closure device 310 is provided that, likethe atrial appendage closure devices 10, 210 shown in FIGS. 1-10,includes an insertion rod 320 having a first end 322 and a second end324. The atrial appendage closure device 310 also includes an occludingmember 330 having an outer surface 332 and an inner surface 334, and ananchoring member 340 that is connected to or otherwise attached to theinsertion rod 320 for securing the device 310 to a left atrialappendage. Unlike the atrial appendage closure devices 10, 210 describedabove, however, the anchoring member 340 of the left atrial appendageclosure device 310 is not in the form of a bolt, but rather has anumbrella-like shape, with the proximal surface 341 being substantiallyflat and the distal surface 342 of the anchoring member 340 having aconvex shape. Additionally, the anchoring member 340 is movable betweena retracted position and a deployed position, as best shown in FIG. 12H,and is configured to slide along the length of insertion rod 320. Inthis regard, upon the insertion of the device 310 and the insertion ofthe occluding member 330 into a heart to provide a seal between the leftatrial appendage and the left atrium of the heart, the anchoring member340 can be slid down the insertion rod 320 and locked to therebycollapse the left atrial appendage 100, while the increased surface areaof the anchoring member 340 provides the added benefit of preventingblood from entering into the left atrial appendage 300 and clotting evenif the occluding member 330 inside the left atrial appendage 100 doesnot completely seal off the left atrial appendage 100 from the leftatrium 110.

Furthermore, with regard to the occluding member 330 of the left atrialappendage closure device 310, unlike the occluding members 30, 230 ofthe devices 10, 210, the occluding member 330 includes a pair of hookedend portions 333 a, 333 b at either end of the outer surface 332 thatassist in sealing off the left atrial appendage 300 from the left atriaof a heart. In this regard, it is contemplated that, in someembodiments, the occluding member 330 can further include radiatingmembers to provide horizontal stability and circumferential members toprovide circumferential stability, and, in other embodiments, can alsohave a biconvex structure when fully expanded so that it seals of theleft atrial appendage while displaying a slightly convex surface to theinside of the heart. Additionally, it is contemplated that the occludingmember 330 can be injected with a liquid or gel to retain its shape(e.g., a liquid or gel that cures or solidifies after injection settingthe shape), can have a membrane or structure that is textured (e.g.,roughened, flecked, or sintered) to promote formation of a native liningto minimize thromboembolic events, or can be covered with a fabric orpolymeric material to promote tissue ingrowth.

In use, the atrial appendage closure device 310 is generally used in amethod of occluding a left atrial appendage by first providing andinserting a large bore needle 500 through the wall 102 of a left atrialappendage 100, as shown in FIGS. 12A and 12B, respectively. The portionof the atrial appendage closure device 310 that includes only theinsertion rod 320 and the occluding member 330 is then provided and theoccluding member 330 is placed in a retracted position, as shown in FIG.12C. The retracted occluding member 330 is then inserted through thelarge bore needle 500 along with the first end 322 of the insertion rod320 until the occluding member 330 is sufficiently placed in the leftatrium 110, as shown in FIGS. 12D-12F. The occluding member 330 is thensubsequently deployed such that the outer surface 332 of the occludingmember 330 assumes a convex shape, the inner surface 334 of theoccluding member 330 assumes a concave shape, and the hooked endportions 333 a, 333 b at either end of the outer surface 332 furtherseal off the left atrial appendage 100 from the left atrium 110, asshown in FIG. 12G. Upon the placement of the occluding member 330, thelarge bore needle 500 is then retracted from the wall 102 of the leftatrial appendage 100, as shown in FIG. 12G.

Subsequent to retracting the needle 500 from the wall 102 of the leftatrial appendage 100, the anchoring member 340 is then provided andplaced in a retracted position, as shown in FIG. 12H. The anchoringmember 340 is then placed onto the second end 324 of the insertion rod320 and is slid along the length of the insertion rod 320, as shown inFIGS. 121-12J. Upon exiting the large bore needle 500, the anchoringmember 340 is then re-deployed until the proximal surface 341 issubstantially flat and the distal surface 342 of the anchoring member340 has a convex shape, as shown in FIGS. 12K-12L. By pushing theanchoring member against the wall 102 of the left atrial appendage 100opposite the inner surface 334 of the occluding member 330, the atrialappendage 100 is then collapsed and the large bore needle 500 is removedfrom the insertion rod 320, as shown in FIG. 12M. The insertion rod 320is then cut away or otherwise broken adjacent to the anchoring member340 to finish the occlusion of the left atrial appendage 100.

The above-described atrial appendage closure devices and related methodsof occluding an atrial appendage, which allow for a left atrialappendage of a heart to be completely sealed off from the left atrium,are important both for preventing clot formation that may otherwiseoccur with atrial fibrillation and for minimizing surgery-relatedcomplications' that frequently occur in left atrial appendage occlusiontherapy. Further, the devices of the presently-disclosed subject matterminimize the risk of puncturing portions of a heart during surgicalplacement as no barbs or similar anchoring mechanisms are inserted intothe inside of the left atrial appendage. Moreover, the devices of thepresently-disclosed subject matter can be provided in one size tothereby eliminate any patient-to-patient variability that is oftenobserved with current atrial appendage closure devices and, inparticular, pharmaceutical agent dosing. Thus, the atrial appendageclosure devices of the presently-disclosed subject matter provide notonly desirable alternatives to current device- or pharmaceuticalagent-based therapies, with the added benefit that complications arisingfrom the implantation of the device are minimized.

The presently-disclosed subject matter is further illustrated by thefollowing specific but non-limiting examples. Some of the followingexamples are prophetic, notwithstanding the numerical values, resultsand/or data referred to and contained in the examples. Additionally,certain of the following examples may include compilations of data thatare representative of data gathered at various times during the courseof development and experimentation related to the presently-disclosedsubject matter.

EXAMPLES Example 1 Prototyping and Preliminary Testing of AtrialAppendage Closure Device Designs in Hearts

Eight candidate atrial appendage closure device designs are fabricatedat the University of Louisville prototyping center for evaluation in pighearts. Pig hearts are procured from slaughterhouses (SwiftSlaughterhouse, Louisville) and the prototype devices are implanted. Theatria of the porcine hearts are cut open and the efficacy of theprototype designs to completely occlude the left atrial appendage, theforce needed to pull out the atrial appendage closure device (anchoringforce), and the ease of deployment are evaluated.

Upon analysis of the results from these experiments, it is observed thatthe candidate designs provide complete occlusion of the left atrialappendage, with a pull out force greater than 6N (i.e., approximatelythe same as a suture), and are easily deployed into the a left atrialappendage. The most promising candidate designs are then selected forcadaver testing and animal experiments.

Example 2 Cadaver Fit Study

An anatomical fit study is performed in human cadavers (45-120 kg, n=4).The candidate designs are implanted using a thoracoscopic procedure.Three ports are positioned: 1 (5 mm) in the third intercostal space, 1(10 mm) in the sixth space at the median axillary level, and 1 (10 mm)in the fifth space on the posterior axillary line. A pericardiotomy isperformed parallel and posterior to the phrenic pedicle to expose theleft atrial appendage. The Marshall ligament is then interrupted withelectrocaudurization. Through the inferior port, the left atrial accessretainer is subsequently activated with immediate step insertion anddeployment of the occluding member of the device under transesophagialechocardiography guidance. The duration, ease of use, and complexity ofthe device is then compared with catheter-based left atrial appendageocclusion devices, and the anatomical positioning, fit and case ofoccluding member deployment, and anchoring force of the devices isfurther evaluated.

Upon analysis of the results from these experiments, it is observed thatthe atrial closure devices: (1) provide complete occlusion of the leftatrial appendage with a pull out force of greater than 6N; (2) can beimplanted in less than 90 minutes; and (3) are rated by the surgeon asbeing considerably easier to insert and manipulate as compared tocurrent catheter-based left atrial appendage occlusion techniques.

Example 3 Acute Animal Study Surgical Procedures

To begin the acute animal studies, test animals (60-100 kg, male, Jerseycalves) first undergo a 14-day quarantine period. Then, the animals areanesthetized with 1-5% isoflurane and 100% oxygen, and a leftthoracotomy is performed at the 5th intercostal space to provide accessand exposure of the left atrial appendage. Heparin (200-300 units/kg viaIV central line) is administered and the atrial appendage closure deviceof the presently-disclosed subject matter is implanted as describedherein above. Echocardiography is performed on each calf to verifyanatomical positioning and fit of the closure device. Fluoroscopy isalso performed to confirm anatomical positioning of the closure deviceduring implantation. In this regard, a vascular sheath is placed in thecarotid artery, and an angiography catheter may be placed in the leftatrium for injection of radiopaque dye (100-150 mL, which may berepeated 3-5 times) for flow visualization during fluoroscopy. After theevaluation period, at necropsy, full gross examination of end organs iscompleted, with particular attention on the left atrial appendage area,where the device is further visually inspected for fit, positioning, andevidence of clots or defects.

Upon analysis of the results from these studies, it is again observedthat the devices of the presently-disclosed subject matter: (1) providecomplete occlusion of left atrial appendage with a pull out force ofgreater than 6N; (2) can be implanted in less than 90 minutes; (3) arerated by the surgeon as being considerably easier to insert andmanipulate as compared to current catheter-based left atrial appendageocclusion techniques; and (4) allow for blood loss to be less than 100ml during implantation.

Example 4 Chronic Animal Study Surgical Procedures

For the chronic animal studies using the devices of thepresently-disclosed subject matter, the quarantine, anesthesia, andimplantation techniques used in the acute studies are again employed toplace the device in the left atrial appendage of the test animals(60-100 kg, male, Jersey calves). In the chronic animal studies,echocardiography and fluoroscopy are performed at the beginning and endof the 14-day chronic study period. Histopathological analyses areperformed on the device surface and the left atrial appendage toquantify endothelialization of device surface, tissue ingrowth, anddevice-related injury

Upon analyzing the results from the chronic animal studies, it isobserved that the devices of the presently-disclosed subject matter: (1)provide complete occlusion of the left atrial appendage with a pull outforce greater than 6N without device fracture or failure; (2) arecapable of being implanted in less than 90 minutes; (3) are rated by thesurgeon as being considerably easier to insert and manipulate ascompared to current catheter-based left atrial appendage occlusiontechniques; (4) allow for blood loss to be less than 100 ml duringimplantation; (5) exhibit no blood leaks at the device-left atrialappendage junction over the duration of the study; (6) show no visibledevice migration; (7) result in no visible injury to the myocardium orembolization in the end-organs in of the animals; and (8) allow for fullendothelialization of the device surface with no or minimalhistopathological damage to the myocardium, thus indicating that thedevices of the presently-disclosed subject matter can effectively beused as part of a method for occluding the left atrial appendage of aheart.

Throughout this document, various references are mentioned. All suchreferences are incorporated herein by reference, including thereferences set forth in the following list:

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It will be understood that various details of the presently disclosedsubject matter can be changed without departing from the scope of thesubject matter disclosed herein. Furthermore, the foregoing descriptionis for the purpose of illustration only, and not for the purpose oflimitation.

1-22. (canceled)
 23. A method for occluding the left atrial appendage ina subject in need thereof, comprising: positioning a retractableoccluding member adjacent an opening to the left atrial appendage in thesubject, the retractable occluding member having a first configurationwhere it is retracted and does not contact the opening of the leftatrial appendage and a second configuration where it is opened andcontacts and covers the opening of the left atrial appendage, wherein inthis positioning step the retractable occluding member is in the firstconfiguration; anchoring an anchor member to the left atrial appendage,wherein the anchor member is connected to the retractable occludingmember; opening the retractable occluding member to the secondconfiguration to cover the opening of the left atrial appendage; andreducing a volume of or collapsing the left atrial appendage by drawingthe anchoring member and the retractable occluding member together whilethe retractable occluding member remains in the second configuration andthe anchoring member remains anchored to the left atrial appendage. 24.The method of claim 23 wherein the retractable occluding member includeswires which radiate outward from one location and a material layerconnected to the wires.
 25. The method of claim 24 wherein the materiallayer is fabric.
 26. The method of claim 24 further comprising applyingbiomaterials to a surface of the material layer.
 27. The method of claim23 further comprising anchoring an outer periphery of the retractableoccluding member adjacent the opening of the left atrial appendage afteropening the retractable occluding member.